1. Field of Invention
The present invention relates to a liquid crystal display (LCD), and more particularly to an active array color filter structure and a fabricating method therefor.
2. Related Art
In recent years, various kinds of flat panel displays have been developed, such as the liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), and electro-luminescence display (ELD). Among these flat panel displays, the LCD has the advantages of high resolution, being light in weight, compact in size, and low in driving voltage, thus it is widely applied in various information, communication, and consumer electronic products emphasizing portability.
Generally speaking, an LCD has two separated and opposite substrates, with a liquid crystal material sandwiched there-between. The two substrates have opposite electrodes. When voltages are applied to the electrodes, an electric field will be generated to penetrate the liquid crystal material. Here, in the liquid crystal material, the alignment of liquid crystal molecules is changed to the direction of the induced electric field according to the intensity of the induced electric field, thereby altering the light transmission of the LCD. Therefore, the LCD displays images by altering the intensity of the induced electric field.
In the manufacturing process, after the color filter substrate and the active array substrate are laminated together, the liquid crystal material is filled there-between. When being laminated, the two substrates must be aligned with each other accurately, and a fixed cell gap thickness must be maintained. Therefore, the aligning and laminating process is usually the step with the lowest yields in the whole process for manufacturing the LCD.
Currently, the LCD tends to have a large size, high luminance, and high resolution. However, when the resolution is increased, the error space will be narrowed, so that the laminating accuracy of the color filter substrate and the active array substrate will be reduced, and the aperture ratio will also be lowered, directly influencing the luminance of the LCD. When the error is increased to meet the requirement of having a large size, the yield of laminating of the color filter substrate and the active array substrate will be reduced.
Referring to FIG. 1, it is a perspective view of a conventional LCD. As shown in FIG. 1, a LCD 100 includes a color filter substrate 120, an active array substrate 140, and a liquid crystal material 160. Here, the color filter substrate 120 is used for displaying colors, and is disposed on the opposite side of the active array substrate 140 and has color filter structures 122, black matrixes 124, and common electrodes 126. The black matrix 124 is disposed between the color filter structures 122. The common electrode 126 has the color filter structures 122 and black matrixes 124 there-on. The active array substrate 140 includes data lines 142, gate lines 144, pixel electrodes 146, and thin film transistors (TFT) T. The data line 142 and the gate line 144 are interleaved with each other to form a pixel region P, where the pixel electrode 146 and the TFT T are disposed. The TFT T is disposed near the intersection of the data line 142 and the gate line 144, and is arranged on the active array substrate 140 into a matrix. It is used as a switch element, to control the switching actions of the pixel electrode 146. Also, a storage electrode 148 and the gate line 144 are overlapped, to form a storage capacitor.
The data line is connected with the source of the TFT, and the gate line is connected with the gate of the TFT. When a scan signal is input to the gate line, and a voltage is applied to the gate of the TFT, the TFT is ON. At this time, the signal line inputs charges from the source of the TFT to the drain of the TFT, so that the voltage is applied to the pixel electrode. Subsequently, the gate line returns to the original state, so that the TFT is OFF. Then, next gate line is turned into the ON state, and the driving operation of the next stage will be repeated continuously.
However, the conventional active array substrate has a problem in that the properties of the TFT change sharply over time. That is, when a voltage is applied to the TFT, the problem of the changing of properties will occur after a time period, which is called the off-characteristic of the transistor. Due to the aggravation of the transistor, the lifetime of the substrate is reduced.